Approximately 1% of all infants have congenital cytomegalovirus (CMV) infection. In symptomatically infected infants, some may have manifestations of central nervous system disease (including deafness, partial blindness, microcephaly, intracerebral calcifications) or of disseminated disease (hematologic abnormality, hepatitis, gastroenteritis) which can also be life threatening or result in serious morbidity. There are no approved therapies for either group of symptomatic infants, although those with CNS disease may be offered a trial of ganciclovir, but even this therapy is not yet approved and can have consequences in itself. Symptomatic infection usually occurs in infants born to women who have primary CMV infection. Reasoning that the lack of passively acquired maternal antibody in these infected infants of women with primary infection is at least in part permissive for symptomatic infection, the scenario in which an infant is born pre-term and therefore prior to receipt of high levels of passive maternal antibody, may be analogous. Hence if the pre-term infant is infected by exposure to CMV in the birth canal or by breastmilk, disease manifestations may be present in the first few weeks of life. The project will enroll 500 pre-term infants, identify congenitally infected infants, follow CMV exposed infants for acquisition of CMV and assess infected infants for clinical abnormalies (including hearing loss, pneumonitis) and laboratory abnormalities (hepatitis, hematologic manifestions). Correlation of congenital infection and peripartum attack rate and level of passively acquired maternal antibody will be assessed as well as semiquantitative assessment of CMV and antibody to CMV in breastmilk and postnatal attack rate in breastfed infants will be assessed.